Belt with rubber and seamless substrate layers

ABSTRACT

An outer solid rubber sheet layer having a maximum thickness dispersion value of 0.04 mm is adhered to an inner resin seamless film layer with low stretchability forming a seamless adhered one piece two layer cylinder. The cylinder is formed by placing the two layers between an outer casing mold and a core mold and applying a pneumatic pressure to the cylinder outside of the core mold for vulcanizing and adhering the rubber to the resin film.

This application is a division of copending application Ser. No. 10/032,741 filed Oct. 22, 2001, incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to belts applicable to intermediate transfer belts or fixing belts for copying machines, printers and so forth.

2. Brief Description of the Related Art

In electro-photographic copying machines and printers, belts are used for transferring or fixing toners. Usually, these belts are formed out of resins with a low stretchability and sometimes they bear coated layers. Since the above-mentioned conventional belts are usually formed out of only resins with no elastic layers, their shapes and sizes are limited, consequently, their applicable areas are limited.

SUMMARY OF THE INVENTION

The present invention objective is to provide belts having no limitations in shapes and sizes, but with high quality.

A belt according to the present invention is made by the following steps:

Forming an elastic solid rubber sheet layer having a maximum thickness dispersion value of 0.04 mm. Laying the solid rubber sheet layer onto a seamless substrate layer, preferably formed from a resin, with relatively low elasticity to form a layered cylinder. Placing the layered cylinder between an outer casing mold and a core mold where the seamless substrate faces radially inwardly, and then applying a pneumatic pressure to the layered cylinder for vulcanizing and for adhering the rubber sheet to the substrate to form a one piece two layer cylinder.

The belt according to one aspect of the present invention is made with the further step of forming a coated layer on the outer surface of the adhered one piece two layer cylinder.

The belt according to a further embodiment of the present invention comprises an outer elastic solid rubber sheet layer having a maximum thickness dispersion value of 0.04 mm and an inner seamless substrate layer, preferably formed from a resin, with relatively low elasticity bonded to the outer layer to form an adhered one piece two layer cylinder.

In a further embodiment, the rubber sheet layer has abutting opposing ends.

In a still further embodiment, the outer and inner layers are vulcanized to each other.

In a further embodiment, a coated layer is on the outer surface of the adhered one piece two layer cylinder

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view showing an outline arrangement of a vulcanizing apparatus used to make a belt according to an embodiment of the present invention.

FIG. 2 is a perspective view illustrating a state where both ends of a rubber sheet and a seamless resin film are laminated and abut so as to be formed a one piece cylindrical body.

FIG. 3 is a flow chart showing a manufacturing process of the belt embodiment.

FIG. 4 is a chart showing characteristic data of a belt according to the present embodiment.

FIG. 5 shows cross-sectional views of belts according to the present embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter the embodiment according to the present invention is described by referring to drawings. In the present embodiment, the manufacturing method and apparatus of intermediate transfer belts and fixing belts used in color copying machines, color printers and the like are explained.

FIG. 1 is a cross-sectional view showing the outline arrangement of the vulcanizing apparatus used in manufacturing the belt according to the present embodiment.

In the figure, reference numerals “1” is a base plate placed on the bottom of the apparatus, “2” is an outer casing mold as a cylindrical outer die and “3” is a core mold as an inner die. A reference numeral “4” is an air bag for applying a pneumatic pressure from outside of the core mold 3 to an unvulcanized rubber 5 as a cylindrical solid sheet and a resin film 6 as a cylindrical seamless sheet base, arranged between the outer casing mold 2 and the core mold 3. A reference numeral “7” is a vulcanizing chamber for vulcanizing the unvulcanized rubber 5 and adhering it to the resin film 6 so as to be formed in one piece by applying the pneumatic pressure from the air bag 4.

In the present embodiment, the resin film 6 with low elasticity, namely, not stretchable or hard to stretch, is used as a substrate and rubber elastic layers are applied to either the outer side, the inner side or both sides of the resin film, consequently to be formed in one piece. The solid rubber is used for these elastic layers, but liquid or paste rubber is not used for these elastic layers. The applied pneumatic pressure generated by expanding the air bag 4 forms the solid rubber and the resin film into one piece.

The unvulcanized rubber 5 precisely formed in sheet form by calender rollers and the like is used as an outer layer for the belt. The rubber layer is later vulcanized to a seamless resin sheet. Since the vulcanized rubber belt bears smooth surfaces attributed to the forming method, the belt is employable without polishing, since the a dispersion value in the thickness of the rubber 5 sheet can be kept less than 0.04 mm.

A manufacturing procedure of the intermediate transfer belt is explained step by step by referring to a process chart shown in FIG. 3.

(Step S1) A CR rubber is formed into a sheet by calender rollers. Dimensions of the sheet, for example, are as follows. Width: 400 mm. Thickness: 0.48±0.02 mm.

(Step S2) The sheet rubber is cut in a predetermined length, for example, 528±1 mm.

(Step S3) The cut rubber sheet and a seamless film are laminated and both cut ends of cut rubber sheet are butted together with a seamless film so as to form a cylindrical shape. A distance “t” between both ends of the rubber sheet is kept 0 to 2 mm as shown in FIG. 2 so as to keep uniform thickness all over the cylindrically shaped rubber sheet.

(Step S4) The abutted cylindrical unvulcanized rubber is placed in the vulcanizing apparatus shown in FIG. 1 and vulcanized.

(Step S5) The outer surface of the vulcanized cylindrical rubber is coated by spraying a fluoride coating material with thickness by 6μ and baked.

(Step S6) Both ends of coated and baked cylindrical rubber is trimmed, thus the intermediate transfer belt with predetermined dimensions is obtained.

Properties of the belt obtained by the above-mentioned procedure are shown in FIG. 4.

The present embodiment can provide the belt with high quality without any limitations in its shape and dimension.

Any seamless film can be used as the substrate without any limitations in materials and dimensions. A plain weave fabric can also be used as the substrate in place of the resin film. Any rubber material can be used as a sheet material for the belt.

The vulcanizing apparatus is capable of manufacturing belts (a) to (d) depicted in FIG. 5. In belt (a) a rubber layer is arranged at the outside of the belt. In belt (b) a rubber layer is arranged at the inside of the belt. In belt (c) rubber layers are arranged at both sides of the belt. The apparatus is also capable of manufacturing belt (d) formed out of only the rubber.

As explained above, the present invention can easily provide the belt with high quality without any limitations in its shape and dimension. 

1. A belt made by the steps comprising: forming an elastic solid rubber sheet having a maximum thickness dispersion value of 0.04 mm; laying the solid rubber sheet onto a seamless substrate with relatively low elasticity while abutting both ends of the rubber sheet to form a layered cylinder; placing said layered cylinder between an outer casing mold and a core mold where said seamless substrate faces radially inwardly; and applying a pneumatic pressure to the layered cylinder for vulcanizing the rubber sheet and for adhering said rubber sheet to said substrate to form a one piece two layer cylinder.
 2. The belt according to claim 1 made with the further step of forming a coated layer on the outer surface of the adhered one piece two layer cylinder.
 3. The belt of claim 1 wherein the seamless substrate layer is formed from a resin.
 4. A belt comprising: an outer elastic solid rubber sheet layer having a maximum thickness dispersion value of 0.04 mm; and an inner seamless substrate layer with relatively low elasticity bonded to the outer layer to form an adhered one piece two layer cylinder.
 5. The belt of claim 4 wherein the rubber sheet has abutting opposing ends.
 6. The belt of claim 4 wherein the outer and inner layers are bonded by vulcanization.
 7. The belt of claim 4 wherein the seamless substrate layer is formed from a resin. 